Additive Manufacturing: Self-Compacting Concrete Through Controlled Heating

IMTS

Share this Article

Researchers from India seek to further improve 3D printing with concrete. In the recently published ‘Additive manufacturing of self-compacting concrete through controlled heating,’ Shashank Shekhar, Manish Kumar, and Rishabh Mathur (all from the Indian Institute of Technology), investigate whether self-compacting concrete may offer better bonding and strength due to heating.

While this study is unique in its focus, many researchers and industrial users have tackled the topic of 3D printing with concrete, from fabrication of concrete panels to the use of geopolymers, to creating on the large scale. The authors point out that many different mixes have been used previously, to include ultra- and high-strength, fiber-reinforced, and more.

Voids between filaments of printed concrete

While improved bonding can be possible with SCC, the initial yield strength is weak, resulting in the need for better strength gain. This can be accelerated with chemical admixtures, but they have the potential to cause ‘choking in the printing set-up.’ The researchers set up a concrete 3D printer in-house at the IIT in Gandhinagar.

“Three self-compacting concrete mixes are considered, which have identical workability but different water-to-cement ratios,” stated the researchers.

Fresh state properties were studied, including:

  • Shape stability
  • Buildability
  • Layer moisture
  • Surface moisture
  • Infrared surface reflectance
  • Early-age shrinkage

Concrete printing set-up at IIT Gandhinagar (adapted from [46])

The heating system is made up of two 1,000-watt quartz radiation heaters, along with six 116 12 V DC fans, and is mounted between the extrusion area and printing platform.

Schematic of the static extruder and the printing platform (drawing not to scale)

Freshly-printed concrete surface before and after heating

Overall, the researchers discovered that a stable layer thickness could be achieved, as buildability was characterized via direct compression and a Vicat penetration test.

“The buildability was greater for a smaller water-to-cement ratio and/or a longer duration of heating. A longer duration of heating would be associated with a greater loss of moisture from the printed layer, and it may adversely affect the bonding between adjacent layers. A sufficient level of buildability was considered achieved when the texture of the printed surface had turned into matt,” stated the researchers. “The same could be characterized through the measurement of surface reflectance of the printed surface. Early-age shrinkage in a printed layer was greater if the layer was subjected to heating for 60 seconds compared to when it was not.

“The strength for the corresponding printed specimen was 61.5 MPa when the direction of loading was parallel to the layers and each layer was heated for 60 seconds. The strength was 49.1 MPa corresponding to 180 seconds of heating. For loading perpendicular to printed layers, the average compressive strength for the two durations of heating was 65.7 MPa and 56.4 MPa, respectively. The average shear strength of the printed cubes was 3.8 MPa (4 MPa) and 3 MPa (3.9 MPa) for the two durations of heating, respectively, and when the direction of loading was parallel (perpendicular) to the layers. The average shear strength of the mold-cast cubes was 4.2 MPa.”

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Additive manufacturing of self-compacting concrete through controlled heating’]

Share this Article


Recent News

Will There Be a Desktop Manufacturing Revolution outside of 3D Printing?

Know Your Würth: CEO AJ Strandquist on How Würth Additive Can Change 3D Printing



Categories

3D Design

3D Printed Art

3D Printed Food

3D Printed Guns


You May Also Like

Featured

Pressing Refresh: What CEO Brad Kreger and Velo3D Have Learned About Running a 3D Printing Company

To whatever extent a business is successful thanks to specialization, businesses will nonetheless always be holistic entities. A company isn’t a bunch of compartments that all happen to share the...

Würth Additive Launches Digital Inventory Services Platform Driven by 3D Printing

Last week, at the Additive Manufacturing Users’ Group (AMUG) Conference in Chicago (March 10-14), Würth Additive Group (WAG) launched its new inventory management platform, Digital Inventory Services (DIS). WAG is...

Featured

Hypersonic Heats Up: CEO Joe Laurienti on the Success of Ursa Major’s 3D Printed Engine

“It’s only been about 24 hours now, so I’m still digesting it,” Joe Laurienti said. But even via Zoom, it was easy to notice that the CEO was satisfied. The...

Featured

3D Printing’s Next Generation of Leadership: A Conversation with Additive Minds’ Dr. Gregory Hayes

It’s easy to forget sometimes that social media isn’t reality. So, at the end of 2023, when a burst of doom and gloom started to spread across the Western world’s...